VARIETIES. 423 



to support itself, and walk on these alone, with the rest of its 

 body elevated perpendicularly. The caterpillar is very plump, 

 and this formation of the legs enables it to take up less room 

 in the leaf; for, notwithstanding its size, it eats only half the 

 thickness of the pulp, and, until it is full grown, they are never 

 entirely pushed out ; for, when taken from its mine before this 

 time, they cannot at first be distinguished. 



The brown mark on the leaf is caused by the epidermis 

 drying, from the insect having eaten the parenchyma, or sub- 

 stance of the leaf beneath ; — the black one by its egesta, 

 which, during its young state, entirely stop up the mine. 

 I first observed this insect in our garden the beginning of 

 last October, when it was very abundant, particularly on a 

 large standard tree, which had almost every leaf mined by one 

 or more of these caterpillars; for several often mine in one 

 leaf, frequently crossing their own paths and those of others. 

 When full grown, which is about the 24th October, it eats out 

 of the leaf, and crawls down the branches and stem, until it 

 has found a convenient place to fix its cocoon. This is the only 

 time when it finds it necessary to make use of its legs, which 

 seldom exceeds an hour, sometimes less. After having found 

 a suitable place, which is generally about the spines and off- 

 sets of the branches, it begins to form its cocoon, by stretching 

 out its body and attaching a thread to the branch ; it then 

 crosses its body to the other side, and there fastens it. By 

 proceeding thus on all sides, keeping the hinder part of the 

 body fixed, it forms the upper part of the cocoon, or that 

 exposed to the weather, which is convex, and generally cir- 

 cular ; the under part is oblong, shaped to hold the pupa, and 

 much smaller than the upper, which projects considerably 

 beyond it on all sides. At one end the threads are not inter- 

 woven, and leave a space through which the pupa can force a 

 passage. This remarkable cocoon is very flat, and at first of 

 a pure white, which is changed by the first shower of rain to 

 light orange ; it afterwards becomes of a deep brown, so nearly 

 resembling the bark of the rose-tree as only to be distinguished 

 by a practised eye. This change takes place very rapidly. 

 When kept dry, the cocoon remained perfectly white, and pro- 

 duced the moth at the usual time, as well as one which had 

 been immersed in water for twenty-four hours. The pupa is 

 light brown, of an oval shape, about a line long, and half that 



